pip install notebookでPyYaml error


anaconda環境でpip install notebookとすると以下のログが出ました。

Attempting uninstall: pyyaml
    Found existing installation: PyYAML 5.1.2
ERROR: Cannot uninstall 'PyYAML'. It is a distutils installed project and thus we cannot accurately determine which files belong to it which would lead to only a partial uninstall.


conda remove pyyaml
conda install pyyaml
pip install notebook